Six members of the same family have died in a murder-suicide after two teenage brothers made a pact to commit suicide and take their family with them.

Allen Police Department said they were called to a home on Pine Bluff Drive in Allen, Texas, at 1 AM Monday morning  March 5, to perform a welfare check.

They said a family friend had called 911 because they were concerned at least one person in the home was suicidal, WFAA reported.

When officers arrived, they found six people dead; two brothers, an older sister, their mother and father, and a grandmother.

Police did not specify the ages of the deceased, except that they ranged from 19 years and above.

While the motive was not immediately clear, Sgt Jon Felty told KRLD they believed the teenage brothers had a murder-suicide pact.

“It looks like two teenage sons entered into an agreement that they we’re going to commit suicide, and that they were going to take their family members with them,” he said.

One brother was 19 and the other was in his 20s, Felty said.

He confirmed that there was no further threat to the public.

Investigators have not specified when the killings took place, but believe it happened some time over the weekend. They also did not reveal how they died.

Police identified the dead Monday as 54-year-old father Towhidul Islam; 56-year-old mother Iren Islam; 77-year-old grandmother Altafun Nessa; 21-year-old Tanvir Towhid; and 19-year-old twins Farbin Towhid and her brother Farhan Towhid.

Police had no record of any previous trouble at the home of the family, who emigrated from Bangladesh.